Steroid

Introduction & Top Questions
History of steroids
Steroid numbering system and nomenclature
Methods of isolation
Determination of structure and methods of analysis
Total synthesis of steroids
Partial synthesis of steroids
Biological significance of steroids
- Sterols and bile acids
- Sex hormones
- Adrenal hormones
- Steroids of insects, fungi, and other organisms
Pharmacological actions of steroids
- Androgens and anabolic steroids
- Steroid contraceptives
- Cardiotonic steroids
Biosynthesis and metabolism of steroids
- Cholesterol
- Steroid hormones
- Steroid metabolism in plants
Structural relationships of the principal categories of steroids
- Sterols
- Bile acids and alcohols
- Estrogens
- Progesterones
- Androgens
- Adrenal cortical hormones
- Ecdysones
- Cardiac glycosides and aglycones
- Toad poisons
- Sapogenins and saponins
- Antiandrogens and antiestrogens
- Glucocorticoids and cortisol

References & Edit History Related Topics

Images

foxglove as a source of cardiac glycoside digitalis

Blister pack of 28 oral contraceptive pills arranged in four rows, with 21 white active pills followed by 7 orange inactive pills. Arrows indicate the order for taking pills.

Structural diagram of a cholesterol molecule showing its four-ring steroid nucleus, labeled A through D, a hydroxyl group, and a hydrocarbon side chain branching from the main structure.

At a Glance

steroid summary

Related Questions

How are plant compounds such as diosgenin used to manufacture steroid medicines?
How are steroids structured at the molecular level?
How are synthetic corticosteroids used to treat inflammatory diseases?
How are the four rings of the steroid nucleus labeled by chemists?
How can anabolic steroid misuse affect fertility and heart health?
How can anabolic steroid use affect bone growth in young athletes?
How can cholesterol deposits contribute to atherosclerosis?
How can progesterone be converted into different steroid hormones?
How can vitamin D deficiency contribute to rickets?
How do androgens influence male sexual characteristics?
How do androgens support sperm production and the male reproductive tract?
How do bile acids help the intestine absorb dietary fats?
How do corticosteroids reduce inflammation?
How do estrogen and progesterone prepare the uterus for implantation?
How do estrogens influence female sexual characteristics?
How do hydroxyl and ketone groups affect the polarity of steroid molecules?
How do mineralocorticoids regulate salt and water balance?
How do progestins regulate events during pregnancy?
How do small structural changes affect a steroid’s biological activity?
How do the testes use progesterone-related compounds to produce testosterone?
How does aldosterone act on the kidneys to conserve sodium and water?
How does cholesterol become the starting material for steroid hormones?
How does cycloartenol function in plant steroid synthesis?
How does estradiol support female reproductive tissues?
How does partial synthesis differ from total synthesis of steroids?
How does testosterone differ from androstenedione?
How does the adrenal cortex produce cortisol and aldosterone?
How does the liver break down steroid hormones?
How is cholesterol converted into pregnenolone in cells?
How is cholesterol made from acetate fragments?
How is pregnenolone converted into progesterone?
How is squalene converted into lanosterol during cholesterol synthesis?
How is steroid hormone production different in the adrenal glands and gonads?
Which five major classes of steroid hormones are derived from cholesterol?
Which organisms must obtain cholesterol or related sterols from their diets?
Why can glucocorticoids suppress immune system activity?
Why can urinary steroid measurements help detect endocrine abnormalities?
Why do bile acids join with taurine or glycine before entering bile?
Why do chemists use alpha and beta symbols when describing steroid structures?
Why is mature mammalian nerve tissue rich in cholesterol?
Why were anabolic steroids developed from testosterone derivatives?
What is an enzyme?
What are enzymes composed of?
What are examples of enzymes?
What factors affect enzyme activity?
What is an amino acid?
What are the 20 amino acid building blocks of proteins?
What is the difference between standard and nonstandard amino acids?
What are some industrial uses of amino acids?
What common diseases are caused by a vitamin deficiency?
What nitrogen-containing bases occur in nucleic acids?

Health & Medicine Anatomy & Physiology

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External Websites

The Nemours Foundation - For Parents - Steroids
Cleveland Clinic - Steroid Injections
Chemistry LibreTexts - Steroids
Patient - Steroids
National Center for Biotechnology Information - PubMed Central - Steroids: Pharmacology, Complications, and Practice Delivery Issues
United States Drug Enforcement Administration - Steroids
Healthline - Types of Steroids: Uses, Side Effects, and Risks Explained
Open Library Publishing Platform - Drugs, Health, Addictions and Behaviour - 1st Canadian Edition - Steroids
NHS - Steroids

Britannica Websites

Articles from Britannica Encyclopedias for elementary and high school students.

steroid - Children's Encyclopedia (Ages 8-11)
steroid - Student Encyclopedia (Ages 11 and up)

Steroid

chemical compound

Written by

Ronald H. Kluger

Professor of Chemistry, University of Toronto.

Ronald H. KlugerAll

Fact-checked by

Britannica Editors

Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree....

Britannica Editors

Last updated

Nov. 12, 2026 •History

Steroid, any of a class of natural or synthetic organic compounds characterized by a molecular structure of 17 carbon atoms arranged in four rings. Steroids are important in biology, chemistry, and medicine. The steroid group includes all the sex hormones, adrenal cortical hormones, bile acids, and sterols of vertebrates, as well as the molting hormones of insects and many other physiologically active substances of animals and plants. Among the synthetic steroids of therapeutic value are...

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